From Biplanes to ApolloThe NASA Langley Historic District

Joseph R. Chambers

National Aeronautics andSpace Administration

From Biplanes to Apollo The NASA Langley Historic District

ByJoseph R. Chambers

Introduction

“We shall send to the moon, 240,000 miles away from the control station in Houston, a giant rocket more than 300 feet tall, the length of this football field, made of new metal alloys, some of which have not yet been invented, capable of standing heat and stresses several times more than have ever been experienced, fitted together with precision better than the finest watch, carrying all the equipment needed for propulsion, guidance, control, communications, food and survival, on an untried mission, to an unknown celestial body, and then return it safely to earth, re-entering the atmosphere at speeds of over 25,000 miles per hour, causing heat about half that of the temperature on the surface of the sun, and do all this, and do it right, and do it first before this decade is out.”—President John F. Kennedy, September 12, 1962.

When President Kennedy made his speech in the football stadium at Rice University in 1962, the public’s enthusiasm and excitement had already been lifted to new heights by his previous speech to Congress in May 1961 when he announced his goal of sending Americans to the moon. However, the aerospace community which had been working diligently on the first American efforts in human space flight clearly recognized the tremendous technical challenges that faced them and held their collective breaths. The subsequent success in meeting this ambitious goal was largely due to decades of methodical, constant advances in technology that had produced the capability for the moon missions. The crown jewels of the effort proved to be the existence of leadership, technical expertise, and special facilities that were already in place or developed during the Apollo Program.

Although the astronauts and scientists of Apollo are well known, the years of critical research and development efforts that preceded the program have not been as well recognized. For example, the first high priority research for the embryonic manned space program was

conducted at the NASA Langley Research Center. The technical leaders of the program were mostly Langley experts who had led aircraft flight research and pioneered developments in rocket technology. Decades of high-speed aerodynamic studies had provided insight into the problems to be faced in Mercury, Gemini, and Apollo missions. Langley’s development of experimental data on aerothermal heating provided breakthrough technology for the design of heat shields for suppression of the incredible levels of heating experienced during reentry into the atmosphere. The aerodynamic integrity of the mighty Saturn launch vehicle and its precious capsule components was investigated across the operational speed range. The Langley concept of rendezvous between two spacecraft circling the moon would define the nation’s approach to go to the moon, and Langley conceived and developed simulators to train our astronauts for the rendezvous maneuvers as well as landing on the moon’s surface.

Man’s trip to the moon began over 90 years ago at a small research laboratory in Virginia where fundamental but vital progress was made in aircraft technologies that would ultimately be the building blocks for manned spaceflight. That small lab became the NASA Langley Research Center (LaRC) which is located on 807 acres of government-owned

The boundaries of the Historic District of the NASA Langley Research Center are depicted in this schematic map. The older East Area facilities at Langley AFB are shown in the inset and the newer West Area facilities are shown by the larger map.

land in Hampton, Virginia. LaRC is comprised of facilities and properties located in two areas approximately 3 miles apart at and near Langley Air Force Base (LAFB). One of the NASA research areas is known as the East Area, which is located on approximately 20 acres of land within LAFB allocated by the War Department in 1917 to NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The second area, known as the West Area, contains the major and more recent facilities of the center. The West Area, which began operations in 1940, is located to the west of the main runways at LAFB. The objective of this booklet is to briefly summarize the history of the LaRC over the first 55 years of its existence from 1917 and includes its contributions to the technological development of manned flight from fabric-covered biplanes to the dramatic moon missions of Apollo. The significance of LaRC’s contributions to aeronautical and spaceflight development has resulted in NASA LaRC being designated a National Register eligible historic district.

The Birth of Langley

Following the first heavier-than-air flight by the Wright brothers in 1903, aviation rapidly advanced as aircraft became more capable in terms of payload, range, and speed. However, little appreciation of the potential applications of this new technology for civil or military missions was apparent in this country. Thus, at the beginning of World War I leadership in aeronautical technology was dominated by European countries. At the start of the war government-funded laboratories had been built in England, France, Germany, Italy, and Russia but America did not consider research in the area important and had not responded. At the time, France had 1400 military aircraft; Germany, 1000; Russia, 800; and Great Britain, 400. The United States had only 23. Dismayed by the situation, prominent scientists such as Alexander Graham Bell, Charles Walcott (Secretary of the Smithsonian), and many members of the National Academy of Sciences began an aggressive effort to rectify the situation. Spurred on by the efforts of this group of visionary scientists and military officers, Congress unceremoniously created a rider to a 1915 Naval Appropriations Act in order to create a new aeronautical advisory committee to organize and direct aeronautical research and development for the nation including an aeronautical research laboratory. With a starting budget of $5000, the advisory committee reported directly to the President, who appointed its 12 members with no salaries. Passed without debate or fanfare, the legislation gave birth to a new agency initially named the Advisory Committee for Aeronautics, which at its first meeting proclaimed itself the National Advisory Committee for Aeronautics (NACA).

After extended studies and debates over 15 potential sites for the research laboratory, the War Department procured 1650 acres of land in 1917 near Hampton, Virginia for the joint use of the Army Air Service, Navy, and the NACA. The site was named Langley Field in honor of early flight pioneer Samuel Pierpont Langley. However, the entry of the United States into World War I caused the military

Surveyors arrived at Langley Field in April 1917 to define acreage for the Army Air Service and the NACA.

services to build research laboratories at other locations. The Army retained control at Langley Field by constructing and operating military air operations. The NACA was allotted a share of the property and began construction of the first civilian aviation research laboratory in 1917, to be known as the Langley Memorial Aeronautical Laboratory (LMAL) within designated areas of today’s Langley Air Force Base.

The construction process proved to be a tremendous challenge because of the isolated location, swampy soil foundation, swarms of mosquitoes, outbreaks of influenza, inadequate housing, and poor relations between the Army and the NACA. Undaunted by these problems, the NACA pressed on with building the new laboratory. Initial NACA construction efforts focused on an administration building, support facilities, and research facilities including a wind tunnel. All buildings were within a block of each other near the shores of the Back River. The NACA officially dedicated its laboratory in conjunction with the completion of its wind tunnel on June 11, 1920. General William “Billy” Mitchell led a 25-plane flyover in salute to the NACA. No one in attendance that day could have possibly foreseen the vital role that this nascent research organization would provide for the nation to achieve significant advances in aeronautical and spaceflight development.

Chapter 1

Forging the Legacy: The Early Years (1922-1939)

The end of World War I signaled a new era of opportunity at the Langley laboratory. The early years of the laboratory from 1922 to 1939 were touched by an environment of technical and political events that shaped the American economy and interest in support for technology. The aviation experiences of World War I, the Roaring 20s, the Great Depression, and the Golden 30s all had powerful influences on the ability of the nation to establish a national aeronautical research laboratory.

Initially, the NACA grasped for a unique role and mission in aeronautics. The agency became involved in all aspects of the early days of aviation, including resolution of patent and licensing disputes, navigational aids, military procurement problems, and air mail experiments. While the agency’s parent committee in Washington struggled to formulate a more specific approach to its mission requirement to “supervise and direct the scientific study of the problems of flight with a view toward their practical solution,” the staff at Langley embarked on technical research involving aerodynamics, aircraft power plants, and flight operations.

A key decision was made when management focused the laboratory’s primary efforts on the field of aerodynamics. Although wind tunnels had been in international use since the 1800s, only two facilities existed in the United States in 1910—the Wright brothers tunnel in Dayton, Ohio, and a larger tunnel at Catholic University in Washington, DC. Langley’s first wind tunnel was primarily intended to educate its inexperienced NACA staff in the fundamentals of aerodynamics and provide initial training with wind tunnel testing while trying to catch up with the Europeans. As a first step, a replica of a 10-year-old British 5-foot-diameter wind tunnel at the British National Physical Laboratory was constructed at Langley for initial aerodynamic experiments. Other than providing a foundation of aerodynamic testing methods and analysis techniques, Wind Tunnel Number 1 produced little in the way of technology advances. In reality, the tunnel was obsolete when it was built. However, with the experience gained using the facility the energetic young scientists of the Langley staff rapidly conceived, advocated, and put into operation a series of innovative new wind tunnels that dramatically leapfrogged existing capabilities elsewhere in the world.

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The First Breakthrough

The first major contribution of Langley to aerospace technology involved the problem of extrapolating aerodynamic predictions from the results of wind-tunnel tests of small-scale models to full-scale aircraft in real-world flight conditions. It was widely known by wind-tunnel experts that the physical inability to simulate a “scaled-down” atmosphere when testing small-scale models could result in errors in predictions of several critical aircraft aerodynamic characteristics—especially those that influenced all-important cruise and landing speeds. More than 20 wind tunnels were then in operation around the world, and their operators all grappled with this troublesome “scaling” issue.

In 1921 Langley researchers proposed a revolutionary wind-tunnel concept in which a conventional wooden atmospheric wind tunnel was placed inside a closed pressure vessel and the air pressurized to levels as high as 20 atmospheres. In this manner, critical physical properties of the air could be changed under pressurization to more accurately simulate full-scale flight conditions. The large outer pressure tank, a massive structure 34 ½ feet long and 15 feet in diameter with steel walls 2 1/8 inches thick, was constructed at the nearby Newport News Shipbuilding and Drydock Company and shipped to Langley by barge. Known as the Variable Density Tunnel (VDT), Langley’s second wind tunnel resembled a giant watermelon housed in a building next to the building containing Wind Tunnel Number 1. Results obtained from the 5-foot test section of the VDT made an immediate impact on advances in aeronautical technology and positioned Langley in an internationally recognized leadership role in aerodynamics. No European country possessed this test capability and individual countries around the world quickly took note of this promising concept. Today, pressurized wind tunnels are routinely used to obtain more accurate aerodynamic data.

Right: The Langley Memorial Aeronautical Laboratory in 1924. The Laboratory building (now Bldg 587) is prominent in the foreground while Wind Tunnel Number 1(Bldg 580) is at the upper right corner of the photograph next to the smaller Variable

Density Tunnel building (Bldg 582). Note the railroad tracks that provided rail service from Langley Field to Hampton.

Overleaf: The Langley Variable Density Tunnel captured the world’s attention with its new test capabilities. A conventional wooden wind tunnel was encapsulated within a massive pressure shell which was pressurized by a

compressor and the plumbing shown in the foreground.

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Langley’s First Collier Trophy

A critical problem of aeronautical research in the early 1920s was poor agreement between data obtained in small-scale wind-tunnel tests and full-scale flight results on propeller performance. The NACA quickly responded to this problem by building a new large wind tunnel which would permit testing of actual full-scale propellers along with their powered engines and supporting fuselage shapes. Known as the 20-Foot Propeller Research Tunnel (PRT) the new test facility was placed into operation in 1927. The building was 166 feet long and 89 feet wide with a height of 56 feet. After the air was pulled through the open-jet test section by an 8-bladed propeller, the flow returned via return passages within both walls. The structure was a wood-walled steel-framed structure, with walls on the inside of the framing so as to permit smooth flow around the tunnel circuit.

The PRT provided data for the first analyses of full-scale propeller performance as well as measurements of engine cooling characteristics and overall propulsive efficiency. The most significant result obtained from testing in the PRT was that a streamlined enclosure (cowling) covering the exposed air-cooled engine cylinders that were in vogue at the time could significantly reduce the aerodynamic drag of the cylinders and their cooling fins. This reduced the fuselage drag of an aircraft by almost one third. In addition, the NACA-developed engine cowling concept provided much better engine cooling with properly designed internal baffling. Initial results of the NACA cowling were first summarized in late 1928 and were quickly disseminated to industry where the cowling concept was immediately applied to some of the nation’s most famous civil and military aircraft. In recognition of this contribution, the NACA was awarded the coveted Collier Trophy by the U.S. National Aeronautics Association. The trophy has been presented since 1911 to those who have made “the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space vehicles, the value of which has been thoroughly demonstrated by actual use during the preceding year.”

The PRT provided many years of valuable large-scale research results on engine cooling and the impact of aircraft components such as landing gear on overall aircraft drag. Another of its important contributions resulted from systematic testing of propeller/engine-nacelle/wing configurations to determine the impact of engine placement on drag. Tests of the engine above, below, and in line with the wing clearly defined the advantages of in-line engine placement, which was rapidly adapted by designers of multi-engine aircraft such as the famous Douglas DC-3.

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The Cave of the Winds

In 1929 the NACA was riding the success of the internationally acclaimed contributions of the PRT and had full support from Congress for more American leadership in aeronautics. Within this favorable environment, NACA management proposed a massive new wind tunnel capable of testing complete full-scale aircraft under powered conditions within an open-jet 30- by 60-foot test section. Little doubt existed that testing of a complete full-scale airplane (which could also be used to obtain data in flight) would be a tremendous tool in aircraft design. In the minds of senior NACA managers, however, an even more important reason for building the world’s largest tunnel would be the visual and political impacts of its existence. Congressional approval to begin construction was easily obtained thanks to the fame of the PRT, and the project was initiated during the years of the Depression. Although labor was plentiful during those years, building the tunnel involved a large expenditure within the NACA budget. The new tunnel would require funding of about $1 million, which was three times the value of the entire existing laboratory at that time including administration buildings, shops, and all the other existing NACA wind tunnels.

Construction methods used by the NACA in the 1930s are typified by this progress print of the Full-Scale Tunnel in 1930. The steel

structure of the tunnel is on the outside of the building which is being covered with sheets of asbestos-impregnated concrete.

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The Langley Full-Scale Tunnel (FST) was constructed in 1930 and became operational in 1931 with the capability to assess the impact of full-scale aircraft components, construction techniques, and aircraft modifications for speeds up to about 100 mph. The tunnel flow circuit was designed for a “double return” concept similar to the PRT in which the airflow from the test section returned to the test section via two return passages within the walls of the building. To achieve smooth airflow within the passages, the steel support members of the exterior walls of the building were located on the outside of the structure, which was covered with sheets of asbestos-impregnated concrete sheets. To the uninformed visitor, it appeared that the wind tunnel had been built inside out.

When the Langley Full-Scale Tunnel (Bldg 643) began operations in 1931 it was the world’s largest wind tunnel. A Vought O3U-1 biplane is shown mounted to the tunnel struts during checkout in early 1931. Toledo scales were used to measure air loads and the tunnel airspeed was controlled with a street car-type switch located at the base of the rear wall.

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The technical objectives that had initially justified construction of the tunnel were quickly accomplished as fabric-covered biplanes and early monoplanes were subjected to intensive testing. Management considered the political reaction to the FST to be a complete success. The facility became a cathedral-like image of the aeronautical leadership that was bestowed on the Langley laboratory and its capabilities, and the world’s most famous designers and military leaders were frequent visitors to the facility.

The lifetime of the FST provides a particularly informative perspective on how investments in research facilities and laboratories at Langley resulted in products and testing capabilities that were totally unexpected during the justification and construction process but became critical for future needs. After only a few years of operations, the FST had completed its initial mission and serious questions regarding the future need for the tunnel began to arise. However, a rapid influx of aircraft designs within the military services in the late 1930s began to generate numerous military requests for assistance from the NACA in areas that could be investigated only within the capability of the tunnel. The FST became one of the most important problem-solving tools for the nation during World War II and many years thereafter. This unique facility became the oldest wind tunnel in the NACA/NASA inventory and labored on for many decades, finally terminating operations at the end of 2009. By that time, its 78-year-old test chamber had witnessed activities that covered the scope of applications from biplanes to manned space flight.

Breakthrough by Disguise

Not all of the NACA’s new ideas were easy to sell to Congress. One new high-priority concept being pursued by the NACA in the late 1930s was a group of low-drag airfoils known as laminar-flow airfoils which promised to dramatically reduce drag at cruise conditions. However, wind-tunnel testing of the airfoils required exceptionally low levels of air flow turbulence. The scientific foundations for the concept were complex and far beyond the understanding of politicians, so efforts to justify and promote construction of a special new wind tunnel with extremely low values of turbulence were not well received by NACA management. Undaunted, Langley technical specialists used growing national interest in aircraft icing problems to justify a new Icing Tunnel—which was carefully designed to promote extremely low values of turbulence.

The Icing Tunnel (Bldg 583) was built with refrigeration equipment and thermal insulation to provide environmental conditions required for icing research, but the geometry of its flow circuit included carefully designed turbulence-damping features. The tunnel became operational in 1938 with a series of icing experiments worthy of its name; however, after these initial tests the refrigeration equipment 8

was removed and flow-smoothing screens and honeycombs were installed resulting in the desired low levels of air-flow turbulence. After the modification, the tunnel became a workhorse for detailed development of laminar-flow airfoils that equipped several famous U. S. aircraft in WWII including the P-51 Mustang fighter. In its new mission, the tunnel became known as the Two-Dimensional Low-Turbulence Tunnel. It would later be superseded by an even more capable Two-Dimensional Low-Turbulence Pressure Tunnel (Bldg 582A) in the 1940s, and the building that housed the Two-Dimensional Low-Turbulence Tunnel would be converted for other uses in the late 1940s.

Meeting the High-Speed Challenge

Interest in the special aerodynamic issues of transonic and supersonic aircraft and missiles began to surface as early as the 1930s. Construction of a large high-speed facility for testing was initially unfeasible because of power consumption and costs, so small specialized wind tunnels were used to provide research capabilities into high-speed regimes of flight and compressibility effects. The first experiments at Langley were conducted using the compressed air that was normally exhausted from the previously discussed pressure vessel of the VDT. Rather than wasting the high-energy pressurized air at the end of a test by exhausting to the atmosphere, the flow was diverted to produce near-sonic speeds in a small 11-inch wind tunnel located near the VDT (Bldg 582). The vertically oriented Langley 24-Inch High-Speed Tunnel (Bldg 585) which was also powered by the blowdown of VDT compressed air became operational in late 1934 and permitted visualization of compressible flow phenomena at near-sonic conditions using a new system known as a Schlieren system to visualize the location and steadiness of shock waves. Success with the facility led to increased interest in high-speed airfoils, but the testing time was very brief and the test subjects were limited to relatively small components. Langley’s first continuous-flow high-speed tunnel was proposed as a “full-speed” (500-mph) companion to the low-speed FST. The tunnel was completed in 1936 and placed into operation as the 8-Foot High-Speed Tunnel. Constructed as a Work Progress Administration (WPA) project and initially capable of speeds up to Mach 0.75, the tunnel later was modified to permit transonic testing. Located near the Back River next to the Full-Scale Tunnel, the tunnel required special consideration during construction to withstand tremendous inwardly-directed pressures induced by the high-speed flow. Rather than using welded steel for the tunnel circuit, the NACA built the entire tunnel of reinforced concrete which enabled the use of unskilled laborers of the Depression years. The test section was enclosed in an igloo-shaped structure with concrete walls a foot thick. The igloo was essentially a low-pressure chamber—just the opposite of the VDT. Test personnel had to wear oxygen masks and enter the test section area through special airlock provisions. As was the case for the

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Full-Scale Tunnel, the initial studies conducted in the tunnel were generic and fundamental in nature; however, when the nation entered World War II the tunnel was invaluable in solving problems for specific aircraft and understanding high-speed compressibility effects in general.

The Langley 8-Foot High-Speed Tunnel (Bldg 640) was the first continuous-flow high-speed tunnel at Langley. The concrete tunnel components shown in the foreground are the tunnel circuit and the igloo-shaped test section. At the left rear is the Propeller Research Tunnel and at the right rear is the Full-Scale Tunnel (Bldg 643).

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Flying Models

Certain problems of flight required unconventional wind tunnels for the prediction and the elimination of serious problems such as unrecoverable tailspins or poor stability and control behavior. Unintentional and unrecoverable spins have been one of the most common causes of fatal accidents since the beginning of heavier-than-air flight. The phenomena involved in such accidents are extremely complex and difficult to measure in conventional wind tunnels.

Inspired by early 1930 British research, Langley pursued the concept of using free-flying models to evaluate spins in a special vertical wind-tunnel facility. In 1935 the Langley 15-Foot Free-Spinning Tunnel (Bldg 646) was placed into operation, using dynamically-scaled free-flight models to assess spinning behavior and recovery characteristics. The 15-foot test section of the tunnel used a vertically rising air stream with the tunnel-drive propeller located at the top of the facility. Aircraft models were launched into the vertical air stream with a spinning motion and the resulting spinning behavior was noted after the model stabilized in a spin. The model’s control surfaces were actuated with internal mechanisms and the ability to recover from the spin was noted. In the case of unsatisfactory behavior, modifications were determined for improved characteristics. Test results from the facility proved to be so informative that the military services required testing in the tunnel for all new designs.

Following the successful implementation of the 15-Foot Free-Spinning Tunnel, researchers extended the use of dynamically scaled free-flying models to include assessments of the dynamic stability and controllability of aircraft in conventional flight in horizontal wind tunnels. Pioneering experiments were conducted with a rudimentary 5-foot wind tunnel in 1937 in Building 646. The concept consisted of using unpowered, remotely controlled aircraft models and a wind tunnel which could be tilted in a nose-down direction to permit a model to fly unrestricted in gliding flight within the airstream. By controlling the model’s attitude and the airspeed of the tunnel, it was possible to maintain the position of the model within the test section so that its inherent stability in response to controls could be assessed.

The experiments proved to be highly successful, and in 1939 the pilot tunnel was replaced with a larger 12-Foot Free-Flight Tunnel (Bldg 644). The new tunnel, which was nestled next to the Full-Scale Tunnel and the Free-Spinning Tunnel, was enclosed in a sphere which provided environmental protection while providing the ability to tilt the test section upward and downward. The 12-Foot Free-Flight Tunnel proved to be especially valuable in assessments of unconventional and radical aircraft designs for which no experience

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base existed. The relatively small power consumption and physical size of the tunnel has resulted in it becoming an ideal laboratory-type facility which is especially valuable for preliminary evaluations of innovative concepts before commitments are required from larger, more expensive wind tunnels. The tunnel is now known as the 12-Foot Low-Speed Tunnel and continues operations to the current day.

Technical contributions made during Langley’s first 20 formative years had tremendous impacts on the development of experimental and theoretical tools for the analysis of aircraft design and problem solving at that time. The field of aerodynamics was changed forever by experimental data obtained from the unique wind-tunnel facilities at Langley. International recognition and awards came forth in response to Langley’s achievements in creating airfoil designs with reduced drag and higher lift capability, drag-reducing cowling concepts, high-lift devices for wings, control concepts for satisfactory handling characteristics at low speeds, and placement of engine nacelles on wings for minimum drag. At the same time, Langley scientists initiated major programs in theoretical studies to advance aerodynamic theory. The technology also produced vastly superior propellers that would prove vital to U.S. aircraft in World War II. Pioneering efforts in high-speed aerodynamics energized a rapid advance in understanding of compressibility effects, supersonic flows, and the “sound barrier.”

These solid first steps in the development of aerodynamic test facilities and expertise evolved into the capability required many years later by the manned spaceflight programs. The seeds of knowledge that had been planted on high-speed flows, shock waves, and stability of blunt-shaped objects would pay off in many ways as guidance for further research in the coming decades. Many of the wind-tunnels constructed in the formative years of the LMAL continued to soldier on through decades to come and were ultimately used to support

The Langley 15-Foot Free-Spinning Tunnel (Bldg 646) was the first NACA spin tunnel. The airstream rose vertically and models were launched by hand (or as shown here on a spindle) into the airstream for studies of spins and recoveries.

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NASA space projects. For example, the FST would test space capsules and recovery systems for landing capsule configurations, and the Langley 15-Foot Free-Spinning Tunnel would be used to study deceleration devices and the stability of parachute/capsule combinations during recovery.

Aircraft Flight Research

The scope of research activities at Langley was not limited to wind tunnels. At the onset of its operations, the NACA recognized the importance of actual aircraft flight projects to produce relevant solutions to the problems of flight. It was well established that results obtained with model aircraft would not be believable unless verified by corresponding full-scale flight results. Of more importance was the fact that certain flight problems and pilot opinions were not amenable to ground-based wind tunnels or research labs. Without sufficient funding to procure its own research aircraft, LMAL successfully borrowed two Curtiss JN4H Jenny aircraft from the Army Air Service at Langley in 1919 for a flight research program to establish correlation between aerodynamic test results obtained with a model in a wind tunnel at MIT and full-scale flight.

Initially two flimsy buildings near the Army hangars at Langley Field were constructed to house the NACA research aircraft. An influx of 17 aircraft (including some captured foreign WWI assets) had been transferred from the military services to the NACA by 1923, beginning a decades-long procession of military aircraft that would be evaluated by Langley test pilots. In many cases, the actual airplane was tested in the Full-Scale Tunnel to obtain aerodynamic data for correlation and understanding of flight results. The NACA finally acquired funding to procure several aircraft for its own research use beginning in 1924. A more modern hangar was then constructed in 1931 at Langley Field to accommodate the ever-growing NACA flight research program.

Products of the flight research program included the first controlled studies of the effects of the environment (turbulence, icing, etc.) on flying characteristics of aircraft, including the development of advanced instruments and data-recording equipment. Assessments of the flying qualities of aircraft were conducted, resulting in modifications to specific aircraft and the production of general design guidelines for future aircraft. Flight evaluations included both land-based airplanes and seaplanes and flying boats. In-flight investigations were conducted to establish correlation with small-scale and full-scale wind-tunnel results in a broad spectrum of technologies such as high-lift devices and lateral control concepts. Langley test pilots rapidly gained experience with a wide variety of aircraft and their previous

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experiences were extremely valued by the military and industry during the development of new aircraft. As a result of feedback from the NACA pilots, a strong interactive relationship was forged for all new military aircraft developments resulting in an ongoing tradition of requests for evaluations. Years later, the technologies and procedures generated by the early aeronautics flight program would help guide the evolution of manned space projects. In fact, many of the key personnel from the early days became leaders in Project Mercury and the Apollo Program. They brought with them expertise in flight operations and communications, handling quality assessments, and flight hardware—especially flight instrumentation.

Data Acquisition

As the Langley laboratory advanced in capability and sophistication, it became a national leader in the science of data acquisition, including the wide diversity of instruments required for measuring physical parameters. For example, Langley’s flight research involved the development and application of instrumentation to measure specific parameters and phenomena related to aircraft operations including aircraft motions and flight parameters, loads, and human pilot performance. Measurements of pressures over the airframe and engine in flight were required as well as data-recording instrumentation for high quality analysis and results. One of the most important early contributions was concerned with the measurement of primary aircraft flight parameters such as airspeed, load factor (g’s), and altitude. Langley initiated research on a new instrument known as the VGH recorder in the early 1920s and applied it during flight testing with great success. The instrument was the forerunner of today’s “black box” used to record critical flight data in commercial transports and is viewed as one of the most important contributions made by the NACA to aeronautics.

Any discussion of the contributions of wind tunnels at Langley would be incomplete without acknowledging the tremendous advances that were made in the development and implementation of advanced aerodynamic instrumentation systems including mechanical and electrical balance systems for measuring aerodynamic forces and moments, pressure-measuring devices such as manometer boards, and flow visualization equipment. Langley’s instrumentation experts were continuously challenged by requests for precision measurements under extreme conditions involving vibration, temperatures, and unsteady aerodynamic phenomena. Many of the laboratory’s instruments and measuring methods were copied by the military labs and industry.

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Early flight research investigations used aircraft borrowed from the Army. In this NACA study a JN-4H Jenny tows a model wing to obtain data for correlation with results from a wind-tunnel test.

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Seaplanes and Hydrodynamic Testing

In the 1920s America’s interest in civil and military seaplanes led to an additional task area for LMAL researchers. Specifically, the takeoff and landing characteristics of seaplanes presented unique new challenges. For example, there was little understanding of the physics of mixed air/water resistance and other special problems of seaplanes such as avoiding water ingestion into engines and water-spray obstruction of vision within the cockpit. In response to NACA directives, Langley constructed another unique facility known as the NACA Tow Tank (Bldg 720) which was placed into operation in 1931 to conduct hydrodynamic research on seaplanes and flying boats. The Tow Tank was similar in many respects to water-channel facilities that had been used within the ship building community; however, this unique research tool used a relatively high-speed towing carriage and, due to its length, required accommodation of the Earth’s curvature during construction. The tank was constructed of steel covered with the corrugated concrete/asbestos sheeting used by the NACA at the time.

The early hydrodynamics testing conducted in the Tow Tank became the cornerstone of technology for the design of seaplane hulls, pontoons, and operational procedures. Although much of the data generated in wind tunnels for land-based aircraft also applied to seaplanes in flight, the takeoff and landing phases of flight required special consideration and understanding. The expertise of the staff and test capabilities of the facility were in demand for virtually all seaplane development programs.Years later as the Mercury and Apollo programs progressed,

Aerial view of Langley Field in 1930 shows construction underway on the Tow Tank in the foreground and the Full-Scale Tunnel at the far end of the basin. The Propeller Research Tunnel is shown directly above the construction sites and the original NACA buildings of the 1920s can be seen near the top of the photograph next to the Dodd Boulevard thoroughfare.

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water recovery of space capsules and their crews at the end of space missions was recognized as a major challenge. The existence of the Tow Tank provided NASA with a test facility for evaluating key water-entry characteristics and crew exit procedures from floating capsules.

The Research Staff and Culture

The pioneering staff of the LMAL in the 1920s began to conceive and conduct technical research programs, although in the early days Langley researchers were not unanimous in their interpretations of the relative importance and future of the lighter-than-air airship versus fixed-wing heavier-than-air aircraft. In those days aircraft were flimsy, troublesome devices with poor payloads and high maintenance requirements. Efforts were made by some NACA staff members to assist the Army Air Service during its operational activities with airships based at Langley Field, including instrumentation for Army flight tests and wind-tunnel testing in the PRT and FST. After 1938, however, the NACA directed Langley’s efforts solely toward aircraft problems.

The principal product of the individual Langley researcher was formal technical reports from which design and problem-solving data and methods could be based. Before a proposed technical report could be released by a researcher, the draft report was subjected to an intense review process in which an editorial committee of four or more members of the Langley technical staff reviewed the document in detail and later gathered as a group to critique the accuracy, grammar, and relevance of the work. Suggestions and recommendations of the committee were provided to the author for modifications followed by an approval of the modified document by the committee chairman. This rigorous process was initiated early at LMAL and adhered to throughout the history of the NACA and NASA, resulting in extremely high quality publications. In addition to wide dissemination of paper documents within industry, the military, and academia, the results of the final technical reports were reported directly to visiting engineers, representatives of appropriate agencies, international technical meetings, and, on occasion, members of Congress.

During its first 20 years the combined professional and nonprofessional staff at Langley grew at a moderate pace from only 27 in 1920 to 524 in 1939. The professional engineering and scientific staff was composed of ambitious, energetic graduates of engineering departments of well-known universities including Michigan, MIT, Auburn, and Georgia Tech. An active NACA recruiting program canvassed campuses for likely candidates, promising the freedom of conducting research in some of the world’s leading facilities. A common characteristic of the young staff was their intrigue with the emerging aeronautical sciences and the ability to do fundamental research without unreasonable managerial restraint. Most of their activities involved on-the-job training with an opportunity to fail while

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working very difficult problems. Many of their breakthrough ideas came about during informal meetings of self-sponsored specialists and lunch-time sketches on cafeteria table tops.

Langley’s staff quickly became well known figures in the local communities which referred to them as “NACA Nuts” because of their geeky behavior and personality traits. However, local residents grew to respect their technical achievements and the notoriety and recognition that descended upon the laboratory and the Tidewater area. The economic stimulus provided by the influx of personnel and contracted local jobs was also appreciated.

The relationship between the staff members and management during the formative years at Langley was especially rewarding. The young staff, consisting mostly of bachelors, introduced a rich social life enriched with frequent parties and life-long personal friendships. They organized active inter-organizational sports, some shared aircraft to fly to work, and many participated in model aircraft hobbies and competition. Management at Langley frequently visited the research facilities during normal working hours because of a personal interest in the technical proceedings. After all, most managers were technically competent and were considered experts in their respective disciplines. On numerous occasions senior managers would visit during after-hour operations such as night shifts in the wind tunnels. Researchers on duty were aware of the possibility of unannounced visits and ran their operations accordingly to avoid embarrassment and the wrath of their supervisors.

The professional engineering staff was extremely appreciative of the efforts of the shops and facility supporting staffs and since organizations typically included all supporting personnel assigned to specific facilities. It was not uncommon for parties to have both professional and blue-collar staff in attendance. During this time the proud tradition of superior craftsmanship by Langley shop personnel was born and maintained by decades of in-house technicians.

After building a solid foundation in aeronautics and a reputation for themselves, many of the early NACA researchers left government service to pursue high-level careers within the aviation industry, academia, and the military. As ex-NACA members began to advance to the ranks of decision makers, they became very influential in importing NACA technology products within their organizations. They

Annual engineering conferences were held by the NACA beginning in 1926. Attendance at this 1934 conference included such notables as Howard Hughes, Orville Wright, Charles Lindbergh, and many executives of the aviation industry.

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also served with great respect on NACA advisory subcommittees to advise the agency on its technical projects and frequently visited the lab for briefings on the latest results and consultation with Langley experts at various facilities.

New breakthroughs in knowledge occurred on almost a daily basis. As word spread of the new technology and tools developed at Langley, visitors quickly came to be briefed. In 1926 the NACA began sponsoring annual engineering conferences designed as showcases for the latest facilities and technical results. The annual conference was a well-orchestrated report to potential users and stakeholders of the NACA investments. Typically, a large gathering of hundreds of the most important individuals in industry, the military, and academia were transported to Langley Field for detailed briefings on the latest technology advances and demonstrations at several facilities. Showplaces such as the Full-Scale Tunnel always played a key role during the conference tours, never failing to impress visitors because of its massive size and impressive test programs. Virtually every manger in the aeronautical community came to participate, with famous aviation names such as Wright, Hughes, Lindbergh, Grumman, Curtiss, Bellanca, Doolittle, and many others.

The Laboratory Campus

The laboratory campus that had begun at Langley Field in 1920 rapidly expanded as wind tunnels, hangars for flight research aircraft, laboratories, and supporting shops came into operation. The original NACA plots within Langley Field were clustered with buildings in relatively close proximity near the banks of the Back River. Located at the southern end of the district were the Administration Building, the Service Building, the Variable Density Tunnel, the Atmospheric Wind Tunnel, the Two-Dimensional Low Turbulence Tunnel, the 24-Inch High-Speed Tunnel and the Dynamometer Lab. The northern end of the district incorporated the large wind tunnels including the Propeller Research Tunnel, the 8-Foot High-Speed Tunnel, the Full-Scale Tunnel, the 19-Foot Pressure Tunnel, the 15-Foot Free-Spinning Tunnel, and the Tow Tank.

By 1937 the LMAL had established itself among the elite aeronautical laboratories in the world. NACA management rightfully proclaimed that Langley’s facilities and expertise were competitive with any foreign capability; however, as war clouds began to gather in Europe and advances in foreign technology became known, it was obvious that the United States had to accelerate its research and development efforts. Langley’s role in securing the freedom of the Nation during World War II became the next link in advancing technologies that would ultimately be required to place a man on the moon.

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In 1939 NACA facilities included the Full-Scale Tunnel, Propeller Research Tunnel, 8-Foot High-Speed Tunnel, and Tow Tank at the bottom of the photo as well as the 19-Foot Pressure Tunnel across from Full-Scale and the well-marked NACA flight hangar at the top of the picture.

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Chapter 2

War and Peace: Accelerating Technology (1940-1958)

The War Years

As the threat of Nazi tyranny began to rise in the late 1930s, the NACA became concerned over the significant increase in aeronautical research and development underway in Europe. The NACA operated an office in Paris at the time under the guise of “liaison” but with the actual intention of conducting aeronautical espionage and providing reports of foreign advances to the NACA management in Washington. By 1936 the reports from the Paris office were alarming. The French, Russians, and Italians had all moved forward with major manpower and facility investments in aeronautical research centers. Of particular concern were several research centers in Germany operated by nearly 2000 well-trained personnel, compared with only 350 at the LMAL. In addition, the data and results produced by the European labs were being actively used by the foreign aircraft manufacturers, resulting in threat aircraft with far greater performance than representative American military aircraft.

Rallying behind these warning flags, the NACA formed special subcommittees to assess the adequacy of America’s national defense in time of war. This resulted in strong recommendations to expand the NACA operations at Langley and to disperse the nation’s aeronautical research facilities so that a single enemy attack would not destroy this vital capability. In addition, recommendations were made to create a second laboratory on the west coast for easier access by industry in that area. The recommendations to expand Langley’s capabilities was acted on immediately, but the issue of the second laboratory was delayed for a few years. The onset and demands of World War II would ultimately have the largest impact on the personnel and facilities of the Langley laboratory until the Russian launch of the Sputnik satellite in 1957.

In 1939 the War Department granted the NACA additional land for the construction of new facilities and support buildings in an area located a few miles west of the original NACA lab, across Langley Field and its runways. The area was subsequently named the West Area and the older lab location became known as the East Area. With the new land acquired and the high-level push to expand its capabilities, the NACA quickly moved to construct new facilities in a flurry of construction activities.

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Several key members of the advisory subcommittees had criticized the NACA for over-emphasizing the aerodynamics discipline in its construction of facilities in the East Area. In their view new research facilities should also include capabilities in the disciplines of structures, materials, and propulsion.

The first building constructed in the West Area was a large brick hangar-like building devoted to research on structures and materials. Clearing for the site began in late 1939 and the Structures Research Laboratory (SRL) was in operation by October 1940. The discipline of structures had become increasingly important as aircraft had rapidly grown in size, weight, and structural complexity in the late 1930s.

The first building in the new NACA West Area was the Structures Research Laboratory (Bldg 1148) in 1940. Also shown in this early 1941 photograph at the upper left are the two buildings of the West Model Shop (Bldg 1150) and in the middle background is the Cloverdale Plantation. Site preparation for the 16-Foot High-Speed Tunnel (Bldg 1146) is also underway to the left of the picture.

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Equipped with load-testing instruments, special floor supports, and a unique “Million-Pound” testing machine, the SRL conducted extensive research during the war on tailored aircraft structures. Investigations of structural components such as stiffeners, ribs, cones, and other parts were conducted by subjecting them to compression, shearing, pulling, and bending to determine strength of the specimen. Even at the height of the war, the studies conducted in the SRL were generally not for specific aircraft (as was the situation for the wind tunnels) but for broader fundamental structures issues such as the effects of structural cutouts, panels, and design procedures. During the war a few complete aircraft structures were tested, including the fuselages of B-17, B-24, and B-26 bombers that were tested on their backs, with their upturned bellies loaded to determine the strength of their undersides for improved survivability during water landings at sea (ditching). The SRL was also used for fatigue testing during the war years, long before structural fatigue became the concern it is today for commercial airliners.

Data acquired during testing in Langley’s Structures Research Laboratory provided unprecedented design information on the effects of structural construction techniques including the impact of cutouts and other structural modifications on the strength of aircraft structures. Operational issues that arose during the war such as structural tail failures and survivability during ditchings at sea were addressed and recommended allocations were submitted. New forms of aluminum and other metals were exhaustively evaluated and applied with great success.

The quest for improved aerodynamic characteristics for military aircraft saturated Langley’s wind tunnel schedules, and new problems had been experienced such as terrifying U.S. pilot encounters with degraded control caused by compressibility effects during high-speed dives. In 1930 Langley had begun operations of a 7- by 10-Foot Low-Speed Tunnel known as the Atmospheric Wind Tunnel (AWT) which was housed in the building that previously contained Wind Tunnel Number 1 (Bldg 580) in the East Area. The research venue of the AWT, which centered on studies of high lift and stability and control, proved to be so important to the military that it was swamped with a test backlog of over four years during World War II. In order to offload the facility, two new 7- by 10-foot tunnels were constructed in the West Area (Bldgs 1212A & B). One tunnel was limited in maximum speed to about 300 mph and the other could operate up to about 675 mph. Known as the 300-MPH 7- by 10-Foot Tunnel and the High-Speed 7- by 10-Foot Tunnel, respectively, they were put into operation in 1942 and 1945 and immediately provided relief for subsonic test requests.

Other Langley subsonic tunnels such as the Full-Scale Tunnel, the 19-Foot Pressure Tunnel, and the 12-Foot Free-Flight Tunnel were all hard at work providing support for the war effort. Historically, one of the most important contributions from the tunnels during the war

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was the drag clean-up studies conducted on full-scale aircraft in the FST. Over 30 military aircraft were subjected to careful analysis to determine the sources of aerodynamic drag and the identification of modifications that reduced the drag penalties.

When the war began, military aircraft had significantly increased in weight, cruise altitude, and size, which resulted in model test parameters that were beyond the capabilities of the original 15-Foot Free-Spinning Tunnel. A more capable 20-Foot Spin Tunnel (Bldg 645) was put into operation in 1941 to accommodate the heavier, larger models. Over 100 prototype and proposed military configurations were tested in 24/7 shifts during the war years with results directly applied to pilot’s flight manuals.

With the successful demonstration of extremely low levels of air-stream turbulence in the Two-Dimensional Low-Turbulence Tunnel, the path had been cleared for the construction of a new, more capable low-turbulence tunnel which also featured pressurization for more accurate testing. Placed into operation in 1941, the Two-Dimensional Low-Turbulence Pressure Tunnel (LTPT) was used to develop more refined laminar-flow airfoils subsequently used on U.S. military aircraft in World War II. More importantly, it served as the birthplace of Langley advances in understanding boundary layer flows on wings and other components.

In 1943 the military services requested that Langley conduct a major research program to determine the ditching characteristics of aircraft configurations and to develop the technology to identify the optimum procedures for forced landings at sea. Many WWII aircraft such as the B-24 bomber and the P-51 Mustang fighter exhibited very poor ditching behavior with a low probability of survival of the aircrew. The program was conducted for several years in Langley’s Tow Tank 2 (Bldg 720-B) which had become operational in 1942. Information from the tests formed the basis for all pilot manuals on the topic during and many years after the war.

As the building effort in the LMAL West Area accelerated in the early 1940s, several specialized facilities were brought online to address specific areas of interest such as the effects of dynamic motions of aircraft on aerodynamic behavior. One such facility was the Langley Stability Tunnel (Bldg 1149), which had the ability to artificially curve the flow around wind tunnel models so as to simulate aircraft motions. This tunnel was especially valuable in studies of new aircraft shapes such as swept wings.

Drag clean-up test underway in the Full-Scale Tunnel for the F4U Corsair. In this test procedure the aircraft was streamlined by removing components, fairing the nose, and taping over structural cracks. By noting the incremental drag caused by features

of the aircraft as the tape was removed, researchers recommended modifications to improve performance.26

Another specialized facility in the West Area was the Langley Impact Basin (Bldg 1192). The Tow Tank research capabilities in the East Area were used to provide extensive information for the design of seaplane hulls, performance during takeoff at sea, and other issues related to seaplane operations. In 1942 Langley constructed the 360 foot long Impact Basin in the West Area to measure loads generated on seaplane components during water landings including impact conditions at various sea states including waves of up to three feet in height. Fortunately for America, the NACA had already turned its attention to high-speed issues caused by compressibility and the

The 16-Foot High-Speed Tunnel was the first wind tunnel to be built in the West Area. It began operations two days before Pearl Harbor was attacked in December 1941.

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facilities required to minimize them. Langley had placed the 8-Foot High-Speed Tunnel into operation in the East Area but the need for high-speed studies outpaced the tunnel’s capabilities. The 16-Foot High-Speed Tunnel (Bldg 1146) was the first wind tunnel built in the new West Area and was completed in December of 1941, just two days before the U.S. entered World War II. Initially designed for the task of investigating cooling problems of full-scale engines and propellers at high speeds (about 500 mph), the tunnel exhibited major problems during its first two years of operation in this mode. The test venue was then changed to tests of isolated full-scale propellers and large-scale models.

As mentioned in the previous chapter, the NACA had conducted supersonic wind-tunnel tests as early as the 1930s in intermittent blowdown tunnels powered by compressed air from the Variable Density Tunnel in the East Area. The new opportunity to expand test capabilities resulted in plans to build a continuous-flow supersonic wind tunnel for the NACA in the early 1940s. The tunnel was to be built at the new Ames Laboratory in California, but a small “model” of the tunnel was constructed at Langley and placed into operation in 1942. The Langley 9-Inch Supersonic Tunnel (Bldg 1191) proved to be an extremely valuable facility for tests of complete aircraft configurations, missiles, and the problems of releasing weapons at supersonic speeds. It was used for the first NACA experimental proof of the advantages of sweep for supersonic performance.

The new West Area facilities required several supporting facilities for the construction of models, large-scale components, and numerous fabrication tasks. Several large high-bay shop buildings were constructed including the West Model Shop (Bldg 1150), the Machine Shop (Bldg 1225), and the Fabrication Shop (Bldg 1232). These facilities were staffed with extraordinarily gifted craftsman that evolved into a world-class workforce that provided dedicated capabilities during the embryonic days of the space program.

Flight research activities of the NACA at Langley during World War II were directed at evaluations of specific military aircraft including prototypes or production-line versions that had exhibited issues or capabilities of interest to the military, industry, and the NACA. Langley’s test pilots had amassed considerable expertise in evaluating handling characteristics, and their opinions were widely sought and valued by the military. Such flights were conducted from the NACA hangar in the East Area which had been constructed in 1931 (now Bldg 750).

In the late 1940s the flight research effort had joined other Langley organizations to provide transonic and supersonic aerodynamic information using flight techniques along with wind-tunnel and rocket-propelled model testing. In flight experiments, research aircraft

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were modified to include small semi-span wing models mounted to special instrumentation on the wings of the carrier aircraft. Supersonic data could be gathered from the model in the accelerated flow over the wing of the full-scale aircraft. Another major effort on supersonic aerodynamics involved dropping models from high altitudes and measuring aerodynamic behavior at high speeds during the free fall.

As Langley pursued the use of drop models and wing-mounted models in flight tests to achieve transonic aerodynamic data, the staff also initiated a third method using rocket-propelled models. LMAL management referred to these rocket models as “pilotless aircraft” and allowed the researchers conducting such tests to explore appropriate test sites for launching potentially hazardous rockets. After a search, the remote beach areas of Wallops Island on the Eastern Shore of Virginia became the prime candidate.

In 1945 Congress approved the establishment of a NACA test site at Wallops known as the Pilotless Aircraft Research Station, and the staff of the Pilotless Aircraft Research Division (PARD) at Langley (housed in Bldg 1232) began excursions to the site for intensive testing of rocket-propelled models. At Langley a building was constructed in the West Area in a location known as the rocket test area (Bldg 1248) where pyrotechnics and rocket systems were studied and developed. Consisting of concrete buildings and bunkers the test area was located near the northern boundary of the West Area.

As an example of the exhaustive flight activities conducted by Langley at Wallops, in one 3-year period a total of 386 rocket-propelled models were tested. Although there were 30 different wind tunnels at Langley, the members of the PARD firmly believed in the superiority of their rocket-launch methods for acquiring information on heating loads and heat transfer, heat-resistant materials, and the aerodynamic behavior of bodies entering the atmosphere. The investment in facilities at Wallops continued to grow and with the creation of NASA it became a separate NASA facility. Once again, some Langley staffers transferred to the spin-off site and became mainstays in the Wallops organization. The pioneering researchers who led the development of the rocket testing technique would later become leaders in Langley’s startup activities for Project Mercury and would then become NASA’s leaders for the Apollo Program.

The contributions of the LMAL during and after World War II in the field of aerodynamics have become legendary. The engineering art and science of reducing aerodynamic drag for improved performance was comprehensively explored and documented in virtually every wind-tunnel throughout the war. Operating problems which included catastrophic failures of aircraft control surfaces and components during high-speed turns were deeply researched, and modifications were designed for immediate retrofit to operational aircraft in the

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field. Engine cooling problems were analyzed in wind tunnels and in flight using specific aircraft. Advances in airfoils by the NACA led to superior military aircraft, and new control concepts provided enhanced safety.

Aerodynamic stability and control problems caused by unexpected aerodynamic phenomena were resolved in high priority tests in ground facilities as well as in flight evaluations. The characteristics of unconventional aircraft designs such as flying wings were thoroughly investigated, and the development of high-lift concepts to achieve lower landing speeds consumed a tremendous amount of facility test time.

Pioneering efforts to achieve reliable transonic, supersonic, and hypersonic aerodynamic design data were clearly among the most important aerodynamic contributions of the laboratory. The development and implementation of slotted walls for transonic wind tunnels, the use of drop models and wing-mounted models for flight extraction of aerodynamic data, and the use of rocket-propelled models were all conceived and implemented by internationally recognized NACA experts.

Research Staff and Culture During WWII

One of the most significant challenges in the history of Langley occurred during World War II as the overwhelming need for additional employees was counterbalanced by an ongoing loss of men to the draft and the very limited availability of qualified scientific personnel. The number of employees at Langley would ultimately triple from 1941 to 1945, but a concerted effort was required to recruit and find a means to defer the staff in order to conduct the intense research and development activities required by the war. Initially, stiff selective service policies ruled the day, and Langley was losing more men to the services than it was hiring. In 1944 arrangements were finally made between the selective service and the NACA wherein all eligible employees at Langley joined the Air Corps Enlisted Reserves and were placed on inactive status at the LMAL where they continued to conduct their research. Although the deferment agreement upset many in the local communities who had lost family members in the war, it stemmed the loss of personnel and helped to maintain an adequate force at the laboratory.

In 1938 a special NACA committee on facilities identified Moffett Field in Sunnyvale, California as the best place for a second NACA laboratory, and its recommendation was authorized in late 1939. In addition, in June 1940 the NACA created a propulsion laboratory

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known as the Aircraft Engine Research Laboratory (later renamed the Lewis Flight Propulsion Laboratory) at Cleveland, Ohio. Staffing for both of the new laboratories would come directly from the Langley rolls. The process took an immediate toll on the Langley work force as the ‘Mother Center” lost many key employees in the staffing process.

As the war waged on, other changes were coming in the makeup of the LMAL work force. In addition to the traditional engineering staff manpower requirements, supporting personnel such as draftsman, machinist, toolmakers, model makers, and others were required. Several hundred teenage boys were brought on in an apprentice arrangement as model makers. The most significant change in the workforce, however, was the large number of women that were employed in support and technical positions. By the end of the war, almost a third of the Langley workforce was comprised of women.

The work environment during the war was extremely demanding with many facilities running on a 24/7 basis. In addition to their normal NACA work hours many employees served with local coastal patrols and military spotting operations. Perhaps the most noticeable change for many researchers during the war years was that Langley’s projects evolved from fundamental, almost scholarly, investigations of generic phenomena to problem-solving for specific aircraft configurations. Although this may have been disconcerting for some, most researchers seem to have taken great pride in the advances they were contributing to the war effort.

Prior to the war the NACA management did not encourage its personnel to serve in consultant roles to the industry and military aviation communities. Rather, they encouraged a fundamental scientific personality in keeping with

Kitty Joyner, mathematician, at Langley in 1952.

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the laboratory image. However, the immense demand for guidance and expertise for high priority development programs and problem solving for specific aircraft overwhelmed management’s recommendations during the war. Industry representatives made frequent visits to the lab to solicit opinions and recommendations from the Langley experts, and interactions with the military were so frequent that a liaison office was established by the Air Corps at Langley for rapid dissemination of NACA results for use by the military. A measure of frequency of industry visits was the fact that in 1935 the daily average of industry visitors averaged three. In 1943 the LMAL was hosting an average of about 45 visitors per day. Other changes in the wartime work environment included a sharp increase in work force sensitivity to security and a laboratory-wide awareness of potential sabotage and espionage efforts.

Post-War Years at NACA Langley

In 1946 a Langley physicist conceived a breakthrough concept called the slotted-throat tunnel to permit reliable testing at transonic speeds. Previously, attempts to test at that speed had resulted in wall interference and tainted aerodynamic measurements to the extent that wind tunnels were useless near the speed of sound. After the concept was proven in the 16-Foot High-Speed Tunnel in the West Area in 1947, the 8-Foot High-Speed Tunnel in the East Area was successfully modified with a slotted test section and was renamed the 8-Foot Transonic Tunnel.

With the revolutionary breakthrough provided by the slotted-throat concept, Langley demolished the old Propeller Research Tunnel and constructed a new pressurized 8-Foot Transonic Pressure Tunnel (Bldg 640) at the site in 1953 to provide for more detailed studies on transonic aerodynamics including studies of buffeting and flutter. In addition to many contributions for military aircraft and the NACA startup of the X-15 program, this facility conducted numerous transonic tests in support of NASA manned space activities.

Immediately after the war the nation experienced a surge of innovation in aircraft design as configurations emerged for higher, faster missions. Langley became deeply involved in cooperative X-plane and Century Series developments with the military. The advent of supersonic fighters, missiles, and bombers required new testing capabilities at supersonic conditions. Arguably, the most productive

Overleaf: Large components of many Langley wind tunnels have been built by the Newport News Shipbuilding and Drydock Company. In this 1952 photo a section of the Langley Unitary Tunnel is under construction with the SS America in the background.

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supersonic tunnel at Langley during the pre-NASA years was the 4- by 4-Foot Supersonic Pressure Tunnel (Bldg 1236) which was placed into operation in 1948. The tunnel and its staff became famous for contributions to the Century Series of fighters (F-102, F-104, F-105, etc.), several research aircraft including the hypersonic X-15, and advanced missiles.

The last major supersonic tunnel constructed in the NACA era was the Unitary Plan Supersonic Tunnel (Bldg 1251) which went into operation in 1955. Originally the tunnel was to be devoted to supersonic missile development, but the demand for specific military aircraft configurations and research aircraft such as the X-15 quickly broadened its research activities.

The advent of supersonic aircraft with thin, flexible wings and high-speed missiles created new problems of structural loading and heating. This stimulated an enormous amount of fundamental materials research at Langley, which would ultimately lead to thermal protection systems—one of the key enabling technologies for the manned space flight program.

One of the most significant events at Langley during the post-war years was the beginning of concerted research in hypersonic aerodynamics. At the end of the war a few key researchers at the LMAL were stimulated by the revelation of extraordinary wind tunnel testing capability for very high supersonic speeds at Nazi Germany’s V-2 ballistic missile center. The LMAL had no such facilities in its inventory. In fact, at that time interest in extremely high (greater than Mach 6.0) speed vehicles was minimal because of the tremendous number of problems to be solved in virtually every discipline. Even the visionary Langley researchers in the field of aerodynamics began to explore hypersonics based only on their personal interest in the unknown.

Many consider that Langley’s entry into space-related research occurred when John Becker conceived the 11-inch Hypersonic Tunnel and it became operational in 1947.

Becker is shown with the facility which produced unprecedented data for hypersonic configurations including the X-15 research airplane.

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A new small wind tunnel to address the issues of hypersonic flight was approved, but with strict limitations on funding. The Langley 11-Inch Hypersonic Tunnel evolved as a “blowdown” tunnel for intermittent tests in this extreme speed range. Now regarded as the birthplace of Langley’s entry into hypersonic aerodynamic/heating investigations, the small tunnel was first tested in the shop area of the old Propeller Research Tunnel in the East Area in 1947. It was later transferred to the Physical Research Laboratory (Bldg 1229) in the West Area where it became a key contributor to the hypersonic X-15 program while developing the hypersonic aerodynamic technology required for manned spaceflight including Gemini.

As the researchers at Langley continued their research endeavors in the late 1950s, the concept of a hypersonic research aircraft evolved between the NACA and the military, and by 1954 the X-15 project was initiated. Although construction of the X-15 began in 1956, the timing of the activity was such that the first flight occurred in 1959, almost a year after the creation of NASA. However, much of the technology and results from the X-15 program have been key contributions to NASA space projects.

By 1957 data obtained in the 11-Inch Hypersonic Tunnel had been used to design candidate concepts for hypersonic “boost-glide” vehicles that used highly swept delta wings and booster rockets to achieve desirable levels of lift during reentry to provide operational landing options. Extensive testing of these configurations occurred in many Langley wind tunnels, and supporting “hot structures” testing began to resolve some of the problems of extreme heating that needed to be overcome. Such designs could not be flown at low angles of attack during reentry because of a tremendous aerothermal heating issue, and a procedure was proposed wherein reentry at very high angles of attack would be used to dissipate the heat on a relatively flat underside. After reentry proceeded to lower speeds the vehicle would be pitched over to lower angles of attack. This procedure was ultimately applied in modern times for the Space Shuttle.

Unfortunately, the boost-glide vehicles of the late 1950s were very complex for the time and would require years of intense research to produce a feasible configuration. When the unanticipated launch of Sputnik occurred in late 1957, the options for a U.S. manned spacecraft quickly narrowed to a less complex blunt-ended space capsule. Although the symmetric capsule could not produce lift or landing options other than a ballistic path, solutions to the heating problem using heat shields was a relatively near-term application

In the late 1950s Langley conducted extensive research for hypersonic boost-glide vehicles. In 1957 a free-flight test to evaluate stability and control of a typical vehicle was conducted in the Full-Scale Tunnel.

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compared to complexities of the high-angle-of-attack technique. In addition, the Atlas intercontinental ballistic missile (ICBM) which was the only U.S. ballistic missile capable of lifting a manned spacecraft at that time did not have sufficient thrust for anything heavier than a relatively small manned capsule.

Spurred on by the growing interest in determining aerodynamic loads and heating phenomena for aircraft and ballistic missiles at supersonic and hypersonic speeds, the NACA constructed a high-pressure multi-cell tank farm in the West Area in 1951 capable of

This complex (Building 1247), originally named the Gas Dynamics Laboratory,

housed the most active hypersonic research group in the nation.  It was the NACA’s

earliest installation with multiple hypersonic wind tunnels and utilized vacuum spheres to give a low starting

pressure for tunnels ranging from six to twenty times the speed of sound.

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maximum speeds of Mach 8. By metering high-pressure air from a central source, several small tunnels could be powered. Today the complex (Building 1247) immediately captures the eye of the visitor because of its huge vacuum spheres which have become a trademark of the West Area.

By 1958 Langley had experienced a rapid growth in the construction of advanced wind tunnels required for studies of new aerodynamic and thermal phenomena and the challenges associated with the growing interest in supersonic and hypersonic flight. Coupled with experiments in the tunnels located in the East Area, the laboratory could cover projected flight characteristics from takeoff to high-speed flight including missions from the atmosphere and reentry. The rapid development of high-speed wind tunnels and the leadership of the LAL staff and their revolutionary hypersonic facilities paved the way with capabilities that were available when the nation required them with great urgency in response to the Sputnik threat.

The most significant accomplishment of the NACA flight research of the 1940s began in 1944 with a series of meetings between Langley’s leaders, the Navy, and the Army Air Forces (AAF) regarding the desirability of a transonic research airplane. At Langley virtually every wind tunnel was immediately impacted by providing supporting data for the emerging project. In addition, instrumentation experts were brought into the planning effort. After considerable negotiations between the NACA, the AAF, and the Navy, the first of three XS-1 rocket-propelled research aircraft was completed in 1945. The AAF selected the test site for flights to be Muroc Dry Lake in California and Langley sent a group of 13 engineers, instrumentation specialists, and observers from Langley to staff its interests at Muroc. The first manned supersonic flight occurred on October 14, 1947, when the AAF’s Chuck Yeager reached a Mach number of 1.06. Following this historic activity, the NACA established a new High-Speed Flight Research Station at the site in 1949, and in 1958 the facility became the NASA Flight Research Center.

Staffing the new flight center created another manpower loss for Langley. Several key leaders and pilots in the laboratory’s flight research and high-speed aircraft organizations opted to move to California and join in the exciting opportunities to test and evaluate emerging jet aircraft of the 1950s. The Century Series of fighter aircraft brought the latest technology and challenges to young Langley engineers anxious to join the glamorous headlines being made at the flight station.

After World War II the NACA constructed a huge new flight research hangar (Building 1244) in the West Area to accommodate an ever-growing backlog of aircraft flight-test efforts. As a measure of the intensity of flight research, in one year during the 1950s a total

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of 54 different aircraft, including high-speed aircraft, were flight tested by Langley pilots. In addition to the large number of flight tests, military bombers and transport aircraft had become extremely large, and a new facility was required to accommodate the flight efforts. The new hangar, which was larger than two football fields, was completed in early 1951. It was designed to be capable of housing two huge B-36 bombers, which were the largest aircraft flown by the military at the time. After the new hangar was put into operation, the NACA hangar and associated offices in the East Area were no longer used and transferred to the Air Force.

The foundations provided by the NACA flight research activities on pilot-vehicle interfaces, cockpit displays, fly-by-wire flight controls, flight-test communications, and many other concepts during the 1940s and 1950s were invaluable inputs to the planning and start-up activities of the NASA manned space activities.

The close relationship that existed between the military services and the NACA enabled Langley to assess the flying characteristics of an extremely large number of aircraft and to evaluate fixes and modifications derived from the Langley staff. An extremely important output of the flight work was the establishment of rigorous procedures for flight investigations involving hazardous conditions and difficult, time-critical decisions regarding “go/no-go” situations. As mentioned in the previous chapter, many of the flight research personnel at the LMAL during the war and in the 1950s became flight directors and program managers during the NASA space programs including the Apollo program. Many of these individuals credit their experiences in the Langley flight program with providing them the professional experiences and work ethics required for the high risk activities they faced in the manned space program.

The West Area Hangar subsequently became a key facility for several manned space projects involving assessments of the capabilities of astronauts to complete their tasks during the Gemini and Apollo missions. As will be discussed in the next chapter, the investigations included rendezvous and docking procedures and training, assessments of the ability to perform extra-vehicular activities, and performing tasks in reduced gravity fields.

As the aircraft flight efforts intensified at Langley near the end of World War II, a new facility was constructed to accommodate measurements of loads on complete aircraft prior and after flight testing. A large hangar known as the Flight Loads Laboratory (Bldg 1220) was used for these efforts with the subject aircraft towed from the flight area to the loads hangar. Constructed in 1945, the loads calibration activities also included a second nearby two-story brick building (Bldg 1219) to house the research staff and its supporting activities.40

When NASA was created, the facilities previously used for aircraft loads measurements were converted to other applications. The hangar subsequently housed advanced aircraft simulators and several other special simulators for the manned space program. To be discussed, the equipment was used for evaluating techniques for extra-vehicular activities and for simulating lunar landings. Meanwhile, the two-story building was converted to office accommodations for other research organizations before it became the site for the Langley Headquarters staff in 1956.

The continued development of specialized instrumentation and data recorders had been nurtured by early NACA management since the 1920s, and the requirement for a specialized facility devoted to instrumentation research resulted in the construction of the Langley Instrument Research Laboratory (Bldg 1231) in 1946. Research was conducted in many fields of instrumentation including pressure, optical, and dynamic measurements. During the 1950s virtually all of the NACA instrumentation was developed within the facility with most of the products used during the startup of the NASA space programs.

Located across from the Instrument Research Laboratory, the Physical Research Laboratory (Bldg 1229) was constructed in 1945 to house specialized equipment used in measurements of loads, flutter, and other fundamental phenomena. When the 11-Inch Hypersonic Tunnel was moved from the East to the West Area, the Physical Research Laboratory was the site of its operations.

In the 1950s it became apparent that aerodynamic heating would be a major barrier to the design of long-range ballistic missiles that would exit the atmosphere after launch and return in a fiery environment as the nose cone and warhead were heated to temperature levels higher than those of the sun. Early efforts by the structures and materials experts at Langley provided some of the earliest guidance in resolving the aerothermal problems that would later challenge attempts to place an American astronaut in orbit and return him safely to Earth.

Recognizing the severity of aerodynamic heating issues, NACA management responded to advisory committee recommendations to construct a new facility for testing large structures at high temperatures. In 1953 authorization was received to begin construction of a new high-temperature tunnel. The Langley 9- by 6-Foot Thermal Structures Tunnel (Bldg 1256) became operational in 1957 and quickly produced unprecedented data on various materials for ballistic nose cones at extreme temperatures (over 4000°F). Applications included components of the X-15 research aircraft and structures for the Project Mercury capsule. To the casual visitor the facility resembled an alien spaceship with several large pressure tanks in a tank farm adjacent to the tunnel.

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In the mid-1950s the NACA converted its old 19-Foot Pressure Tunnel in the East Area (Bldg 648) to a special test facility to study phenomena associated with aeroelasticity and loads. The 16-Foot Transonic Dynamics Tunnel used several advanced concepts to explore characteristics of aircraft and launch vehicle concepts including a slotted test section, an airflow oscillator, and gust response instrumentation. The growth of expertise in this facility proved to be invaluable for flutter clearance testing of military aircraft prior to production and to studies of the effects of external winds on the structural behavior of launch vehicles for manned space applications.

By the end of 1957 the immense expansion of Langley had completely changed the appearance and size of the laboratory environment. The East Area facilities continued to soldier on with their asbestos-impregnated concrete structures and a sprinkling of newer brick buildings. Some facilities such as the old Propeller Research Tunnel and the Icing Tunnel had been demolished and new facilities built at the sites, and others such as the NACA flight hangar had been vacated and inhabited by Air Force personnel of Langley Air Force Base.

The appearance of the newer West Area was in contrast to the East Area, with modern brick buildings, a conference center, and sleek new wind tunnels. The landscape was dominated by huge high-bay shops, a gigantic hangar, and the vacuum-tank farm of the gas dynamics facilities. The offices of the Langley Director had been moved from the old administration building in the East Area to a renovated area within the Aircraft Loads Laboratory office building in 1956. The administrative organizations had been split into West and East Area locations.

End of an Era

On October 4, 1957, the Soviet Union launched Sputnik, the world’s first artificial satellite to orbit the Earth. The event had an immediate and lasting impact on the NACA and its technical programs, research staff, and facilities. When Congress established the National Aeronautics and Space Administration on July 16, 1958, the National Advisory Committee for Aeronautics was dissolved, but its contributions and technical achievements would carry directly over into the manned space missions of NASA with great momentum. Known for its “one stop shopping” variety of technical disciplines, Langley stood ready to support the space program. The legacy of expertise and facilities associated with technology such as boundary layer analysis, drag reduction, water landings, hypersonic aerodynamics, hot structures, vibration and flutter, and stability and control were directly used in the startup of the new agency which faced monumental challenges in a new field —space flight.

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Chapter 3

The Space Age: To the Moon (1958-1972)

On October 1, 1958 more than 8000 NACA employees across the nation awoke to find that their agency had been abolished and replaced by a new National Aeronautics and Space Administration. At Langley, employees gathered to be sworn in as members of the new organization as the era of aeronautics ended and the focus and culture of the new NASA Langley Research Center would all undergo dramatic changes. The reorganization had been anticipated by organizational leaders for several months, and the workflow and transition in Langley’s facilities went very smoothly on that day. Most employees felt it was just another day at work.

Many of the facilities required for the initiation of the nation’s space program were already in place at Langley, but the new emphasis on space projects would result in several new facilities and a major change in the work culture including the organizational structure, management of large projects, the diminished role of aeronautics research, and the exodus of personnel to other NASA space centers. In addition, a few key Langley managers from the legacy aeronautics program later left the new agency rather than switching their interests to space-related projects.

Project Mercury

In 1958, Langley researchers had already been at work for several years on space-related topics, spurred on by scientific interests in satellites, spacecraft, and ballistic missiles. Major changes were immediately planned in the work units to direct their activities toward the new priorities of the NASA mission. Soon after its formation NASA created a special group of 35 senior technical people at Langley to formulate and carry out with great urgency a program to develop and demonstrate a manned satellite. Prominent leaders of Langley’s Pilotless Aircraft Research Division were chosen to lead the effort, and they quickly identified preliminary technical concepts and key personnel for the new group which would manage the endeavor. The objective of the activity would be to successfully orbit an astronaut in satellite fashion and return him safely at the end of the mission. The new organization that would carry out the plan was known as the Space Task Group (STG).

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After a brief stay in 1958 in the offices of the Unitary Plan Supersonic Tunnel building (Bldg 1251) in the West Area, the original 35 members of the group moved to the East Area where they occupied many of the old NACA buildings. The director of the STG had offices in the historic two-story brick NACA Administration building (Bldg 587) that had housed the first Langley administrator from 1920 to 1956. Virtually all of the tenants of the old building were moved to the West Area to make room for the STG staff.

Following extensive reviews and interviews of hundreds of candidates, seven astronauts were chosen by STG management for special training at the research center. With great fanfare the astronauts arrived and resided with their families in the area while receiving the specialized training required for the Mercury mission.

By 1959 over 300 people had joined the new STG and the impact on Langley’s research facilities and office buildings in the West and East Areas became very large. When the seven Mercury astronauts arrived at Langley they were provided a shared office on the second floor of the East Area building that had previously been the site for

The seven Mercury astronauts arrived at Langley for intensive training for their demanding mission. While at Langley they were housed in the East Area building

that had contained Wind Tunnel Number 1 (Bldg 580).

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NACA Wind Tunnel Number 1 and the 7- by 10-Foot Atmospheric Wind Tunnel. Many other East Area buildings became offices for STG members including some Air Force facilities.

In addition to a large presence in the East Area, the STG enjoyed high priorities in the NASA shops, wind tunnels, instrumentation labs, and administrative support. The impact of the space program on Langley’s work force also was evident in the split between aeronautics and space efforts. In 1959, the accelerating space efforts consumed about 64 percent of the total Langley workload, compared to just 36 percent for aeronautics. The swing toward space would grow even larger during the Apollo Program.

Senior managers of the STG inspect a capsule model in the Langley West Model Shop. Left to right the managers are Charles Donlan, Bob Gilruth, and Max Faget.

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The STG organization reported directly to Headquarters and was not formally a part of the NASA Langley Research Center. However, as the planning for Project Mercury matured, the entire Center quickly provided the development and research required for the project. One of the major issues to be addressed by NASA was the configuration for the vehicle that would protect astronauts during the unimaginable heat that would be encountered during reentry. Langley researchers had earlier contemplated delta-shaped lifting vehicle concepts that would be capable of extensive return options including the ability to perform a landing on runways. However, it was widely recognized that the development of such a vehicle would require a considerable amount of research and development efforts and precious time which the nation could ill afford. Management of the STG successfully advocated for a ballistic blunt-faced manned capsule configuration for the mission because of its simplicity compared to the winged or lifting body shapes. In particular, the problem of reentry heating could be addressed with heat-shield or heat ablation techniques.

By 1958 the technical leaders of the STG recognized that the cost of using Atlas-type boosters for numerous development studies to ensure the safety of the booster/capsule system would be far too expensive for the program. Instead, a relatively low-cost approach to evaluate the structural, stability, and crew escape issues involved in the powered launch and reentry of full-scale capsule concepts was required. Conceptual candidates for alternatives led to a relatively low-cost booster/capsule approach for the developmental studies. Known as Little Joe, the engineering tool would prove to be invaluable to the start-up activities. The rocket booster configuration that resulted from the in-house studies included a cluster of four rockets with stabilizing fins. The detailed design and fabrication of the booster was conducted on contract, and five prototype capsules and instrumentation were fabricated in Langley shops. Managed by the STG with extensive support from Langley and Wallops, the Little Joe Project also included flights of rhesus monkeys and biological experiments.

Project Little Joe was a critical learning experience for the STG researchers. Launches from Wallops of Langley-fabricated capsules provided timely information for fabricating the Mercury capsule.

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Although the flight project experienced several failures, it was regarded as an integral part of the learning process for Mercury through 1961. After a series of experimental flights, the project turned to qualification flights for the Mercury capsule.

As discussed in the last chapter, construction of new facilities at Langley—especially wind tunnels—had occurred at a rapid pace during and after World War II. Existing capabilities, which ranged from low-subsonic speeds to hypersonic speeds were immediately applied to the challenges of Project Mercury. In 1959 wind tunnels, arc-jet facilities, and other labs began providing detailed design information on the aerodynamic and thermal characteristics of the Mercury capsule configuration.

Typical activities included tests of a full-scale Mercury capsule replica in the Full-Scale Tunnel as well as detailed evaluations in other tunnels of the behavior of the capsule/escape system during potential aborts. Other tunnels and arc-jet facilities provided information on stability, heat transfer, pressures on the heat-shield structure, and control requirements. Rocket-boosted models were used by the STG at Wallops to determine the behavior of the capsule during reentry as well as detailed pressure and structural characteristics. Water-landing behavior of the Mercury configuration was evaluated using the Tow Tank, and initial training for astronauts to escape from the floating capsule was also conducted.

Considerable work was expended to define an appropriate recovery parachute system that would ensure safe rates of descent down to water impact while providing stabilized motions for the astronauts within the capsule. During the late 1950s experiments had begun in studies of the ability of parachutes to stabilize descending shapes. Unfortunately, testing and analysis in the 20-Foot Spin Tunnel revealed that the blunt-ended shapes of capsules were subject to wild oscillations and instabilities in vertical descent without stabilizing systems. The tunnel was extensively used for parachute system evaluations during all manned spaceflight programs, including Mercury, Gemini, and Apollo. The recovery parachute system for spacecraft had to be carefully designed to prevent potentially catastrophic instabilities and crew discomfort during low-speed recovery operations at the end of space missions. Additional tests involved extensive investigations in the local Back River as well as drop tests of full-scale capsule and recovery systems in the Atlantic Ocean near Wallops

One of Langley’s most important technical contributions to Project Mercury was the development of the astronaut “couch” which was a special fitted seat designed to help him withstand the g-loads encountered during launch and reentry. Conceived by the STG, the couch concept placed the astronaut in a reclined position within the capsule at an attitude most favorable for tolerating loads. A key feature of the concept was a special couch which constrained the astronaut in the desired position. Individual couches were prepared for each of the

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seven Mercury astronauts in the Langley West Model Shop using an innovative foundry procedure. The specially fitted seats were refined and ultimately evaluated by the astronauts during high-g tests on the Navy centrifuge at Johnsville, Pennsylvania.

In addition to tremendous efforts in aerodynamics, structures, and materials, other new challenges had to be met. One particularly challenging area was how to establish a continuous communication network as the Mercury capsule orbited the Earth and how to formulate appropriate communication procedures with the astronaut and trackers during the mission. With an extensive effort, the STG engineers successfully implemented the international political agreements necessary for tracking stations and established Mercury Procedures Trainers at Langley and Cape Canaveral for simulation sessions for the tracking network. At Langley, a large simulator room was constructed outside the airflow circuit within the huge building of the Full-Scale Tunnel. Within the room a Mercury capsule simulator and extensive computer and communications equipment were used for training the project team members during full-mission simulations. Early experiences with the procedures trainer revealed that comprehensive communications were much more difficult than anticipated, and the trainer proved to be invaluable in refining the interactions and ensuring mission success.

Alan Shepard became the first American in space during a sub-orbital flight launched by a Redstone rocket on May 5, 1961. In September 1961, amidst extremely controversial and heated politics, NASA announced that the STG would be moving to a new facility to be known as the Manned Spacecraft Center (later renamed the Johnson Space Center) in Texas near Houston. That fall, over 700 Langley employees were moved to Texas. The departure of the STG members resulted in extensive hiring to re-staff Langley—for example, over 400 new professionals were hired in 1962. However, the loss of the STG and the seven astronauts was a bitter pill for the local Peninsula area to swallow.

After the STG and Project Mercury began to depart for Houston from late 1961 to mid-1962, the local community still considered the individuals and project as its own. John Glenn’s historic Mercury flight launched by an Atlas rocket in February 1962 was the first orbital flight by an American. Local enthusiasm reached a fever pitch, and a huge parade was given on March 17 to honor the seven astronauts. As a final salute, Hampton renamed its main thoroughfare Mercury Boulevard and six local bridges were named for individual astronauts.

The seven Mercury astronauts and Bob Gilruth (right) inspect their specially fitted couches at the West Model Shop. The couch concept was conceived by Max Faget of the STG as a means of absorbing g-loads during the mission

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When Project Mercury ended in 1963, the ex-Langley senior management at NASA’s Manned Spacecraft Center in Houston formally thanked Langley for the tremendous amount of support that had resulted in the success of the program. The leadership of Langley personnel in organizing the STG and managing Project Mercury set the tone for the follow-on projects and paved the way by providing urgent answers to the most perplexing questions regarding manned spaceflight. Langley’s technical expertise and dedicated support for the project enabled the STG to smoothly transition to the Manned Spacecraft Center and to proceed with total support for Project Gemini.

Project Gemini

In 1961, while Langley was attempting to meet the extraordinary challenges of orbiting an astronaut around the Earth, President Kennedy unexpectedly announced that the nation would land a man on the moon and return him safely to Earth within the decade. Leaders of the STG at Langley were stunned. The seemingly impossible task of transporting a human being to the moon and back was far beyond the capabilities that were still evolving in Project Mercury. Several groups were immediately set into motion to address the considerable number of unknowns associated with the mission.

One of the most important questions was what procedure to use to achieve the lunar landing and how to accomplish the task within the decade. As early as 1960 controversial concepts for flights to the moon had been argued and debated at length across NASA. Some proposed that a huge rocket should be fired directly to the moon, land, and take off for a return trip to Earth. This approach was far beyond any U.S. rocket capability envisioned for the decade and would require a lengthy development of a massive new launch vehicle known as Nova. An Earth-Orbit Rendezvous (EOR) concept was also proposed with two spacecraft being launched into orbit, sharing payloads for construction of a vehicle which would take the crews to the moon and return them to Earth. If the space program had been controlled by scientific and technical reasoning and not by political considerations, this approach would have been the next logical development. The moon mission would have ultimately been accomplished—although not in time for Kennedy’s commitment—and a space station would have positioned the nation for additional space program options following Apollo. Also proposed for the Apollo mission was a third concept known as the Lunar-Orbit Rendezvous (LOR) technique, consisting of launching three small spacecraft using a three-stage rocket. The spacecraft would serve as a command module, a service module, and a lunar lander. After achieving Earth orbit, the service module would propel the a three-man crew into lunar orbit, where two of the 52

crew would descend to the moon’s surface and later return to rendezvous with the command module crewed by the remaining astronaut for the return to Earth. Considered by many to be too complex and risky for the moon mission, the LOR required an extraordinary advocacy effort against seemingly overwhelming opposition. The concept of a two-vehicle rendezvous was ultimately shown to be

Langley’s John Houbolt became one of the central figures of the Apollo program when his Lunar-Orbit Rendezvous concept for the mission was adopted.

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as safe as direct missions and was a more timely method. After numerous briefings and heated discussions the LOR technique was ultimately supported by top NASA management in 1962.

The daunting challenge of conducting a spacecraft rendezvous over 200,000 miles from Earth required precise maneuvers and robust equipment. NASA’s Project Gemini was formulated to provide the skills and techniques necessary to transition from the relatively simple ballistic flight requirements of Project Mercury to the complex LOR tasks of Apollo. The specific objectives of the Gemini program were to develop techniques required for rendezvous and docking, experience spacewalking, and examine the effects of long-duration flights that would be required by Apollo missions.

Although Gemini did not result in the construction of new buildings at Langley, the importance of simulation for the potentially catastrophic rendezvous and docking maneuvers resulted in a large number of piloted simulators and equipment being used in existing buildings

The first step in conducting research for a rendezvous in space had consisted of the fabrication of a 50-foot diameter inflatable radome in the West Area Hangar equipped with projection equipment for astronaut familiarization of star backgrounds.

The Langley Rendezvous Docking Simulator was the prime training device for astronauts facing the task of orbital rendezvous for the journey home after the moon landing.

In 1963 Langley constructed the ingenious Rendezvous Docking Simulator (RDS) to permit studies of docking maneuvers for two spacecraft. Its initial application was for Project Gemini and involved docking of the two-man Gemini spacecraft with an Agena rocket booster. Later it was used for studies of the docking maneuvers for the Apollo Lunar Excursion Module and the Apollo Command Module. Consisting of an overhead carriage running on a 210-foot track and a creative cable-suspended gimbal system, the simulator was suspended from the roof of the West Area Hangar. Combining hydraulic and electrical drives, the RDS provided docking capability in three dimensions. Full-scale replicas of the spacecraft could be hung from the simulator within the gimbal system.

Space historians agree that it would have been impossible to meet Kennedy’s challenge on time without using the LOR concept. To accomplish this bold challenge, the astronauts required extensive practice for the rendezvous and docking maneuvers as provided by the RDS. Looking back on the experience, the researchers and astronauts found that the rendezvous task was not as difficult as anticipated by the scientific world. After the Gemini work was completed the simulator was used to train the Apollo astronauts.

In the 1960s researchers continued to explore other concepts for reentry and landing of returning spacecraft. In particular, during the Gemini activities, the potential application of flexible wings to provide gliding capability to enhance the landing options for capsules stimulated a broad research program at Langley. Several flexible wing (parawing) configurations were proposed including all-flexible gliding parachutes and flexible wings strengthened with rigid leading edges and keels. Wind tunnel tests to evaluate the performance, stability, and control characteristics of parawing applications to generic capsule shapes as well as the Gemini and Apollo capsules were conducted in several tunnels at speeds ranging from low subsonic to supersonic conditions.

In addition to conventional aerodynamic testing, unique investigations included free-flying model tests in the Full-Scale Tunnel and drop tests of a large parawing at a nearby abandoned Air Force bombing range known as Plum Tree Island. Outdoor drop-model studies were also conducted to examine the possibility of using deployable parawings for recovery of Saturn boosters for the Apollo Program. After several years of intense evaluations, technical issues involving poor handling characteristics in flight and deployment of the flexible wing ultimately resulted in serious doubt that parawings were appropriate for the Gemini mission and activities were canceled in 1964.

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The Apollo Program

As the ambitious Apollo program accelerated, Langley’s unique wind tunnels became vital participants of the action plan to ensure the safety of the launch vehicle and the component modules. In particular the transonic, supersonic, and hypersonic tunnels acquired detailed design data for the launch vehicle and modules. Facilities such as the Langley Helium Hypersonic Tunnel, the 20-Inch Mach 6 Tunnel, and the Mach 8 Variable Density, together with the Unitary Plan Supersonic Tunnel conducted extensive testing. Other remarkable tests included an investigation in 1963 in the 16-Foot Transonic Dynamics Tunnel of the effects of ground-wind loads on the assembled Apollo/Saturn configuration and the launch tower. The TDT also conducted aeroelastic tests of the Saturn to determine buffet and flutter characteristics. Once again, the 20-Foot Spin Tunnel was used to determine the parachute system details to be used for Apollo.

In 1961 a research program known as Project FIRE (Flight Investigation Reentry Environment) was initiated to address the critical issue of the magnitude and rates of reentry heating on the Apollo spacecraft. Designed as a combined wind-tunnel/flight investigation, the project included suborbital reentry flight using a subscale model of the Apollo Command Module to obtain detailed heating data in flight. During the flight program auxiliary heat shields were used to protect the Apollo model during reentry until test conditions had been met at which time the shields were released and detailed measurements of the magnitude and rate of the heat buildup were taken. The Langley 9- by 6-Foot Thermal Structures Tunnel and the Unitary Plan Supersonic Tunnel were key ground test facilities for the project. Two flight missions were flown in 1964 and 1965 from Cape Canaveral, successfully indicating that the radiation and temperatures to be experienced by Apollo during reentry would be less severe than had originally been expected.

The aerodynamic integrity and safety of the Apollo launch vehicle and modules were ensured by timely and exhaustive testing in many of Langley’s wind tunnels. All aspects of the moon mission from potential abort maneuvers from the launch pad to exit from the Earth’s atmosphere and reentry to a safe landing were evaluated during tunnel tests.

In 1963 NASA announced a new Lunar Orbiter project designed to provide information on the lunar surface conditions in preparation for determining the most suitable landing sites. The project was contracted to the Boeing Company with Langley assigned as the program manager. Although several leaders in the aerospace community questioned the ability of an aeronautics center to lead a major space

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Above: Langley’s specialized facilities provided critical data for Apollo. Here the Saturn V launch vehicle is being tested to evaluate the effects of ground winds on the dynamic structural behavior of the vehicle in the 16-Foot Transonic Dynamics Tunnel.

Left: Project Fire included tests of an Apollo capsule model in the Langley 9x 6-Foot Thermal Structures Tunnel in 1962. The auxiliary heat shields were scheduled to be removed After reentry heating conditions were met.

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project, Langley and Boeing conducted what is regarded as one of the most important contributions to the Apollo program. Five Lunar Orbiter missions were launched between 1966 and 1967. All the missions were successful and 99% of the moon was photographed at high resolution. During the missions, the first pictures of Earth from space were recorded serving to inspire the international community.

This view of the Earth from the Lunar Orbiter I spacecraft on August 23, 1966 was the first picture of the Earth taken from space.

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Immediately after the nation made its 1961 commitment to land men on the moon, Langley researchers began activities to define how the moon landing could be simulated for pre-launch training. Paramount to this analysis was the fact that the gravitational attraction of the moon is only one-sixth that of the Earth. In order to properly simulate the reduced gravity field, it would be necessary to artificially support five-sixth of the weight of a piloted simulator vehicle representing the Apollo Lunar Excursion Module (LEM). Langley experts in the field of flight mechanics devised a brilliant concept wherein a suspension system would be used to support five-sixth of the weight of the vehicle. A typical simulation session would involve letting the vehicle fall freely under a steady acceleration of one-sixth g until the descent rate reached the desired value to begin the landing run.

The development of the simulator concept first involved checking out a simple conceptual set up of a suspended “flying chair” in a return passage of the Full-Scale Tunnel—a task never envisioned by the tunnel’s design team in 1929. After a successful evaluation of the concept, in 1965 NASA Headquarters approved the construction of a new Lunar Landing Research Facility (LLRF) in the Langley West Area.

The LLRF consisted of a 250-foot high, 300-foot long A-frame gantry equipped with the conceptual suspension system and a Lunar Landing Research Vehicle (LLRV) for simulations of the LEM moon landings from an initial altitude of about 150 feet.

The Langley Lunar Landing Research Facility was used by 24 astronauts in day and night simulations of the moon landing and is regarded as one of the most important facilities used by the Apollo program.

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Piles of cinders and dirt were carefully placed on the ground to simulate lunar craters and terrain. In addition, tests were made at night with special lighting to simulate sun-induced shadows that would be present during the moon landing. Twenty-four astronauts used the facility to evaluate piloting problems they would encounter during lunar landings and establish proficiency in landing techniques. The astronauts stated that the simulation was extremely helpful in training for their missions, especially with regard to the lunar landscape cues which appeared very similar to the LLRF visual display.

At the same time that Langley developed its LLRF, a second concept for simulating the lunar landing was pursued by the NASA Ames Research Center. The training vehicle, called the Lunar Landing Training Vehicle (LLTV) was a free-flight simulator in which a turbojet engine supported five-sixth of the vehicle’s weight. While this approach provided training from higher initial altitudes, no safety backup was provided other than an ejection seat for the pilot. Two of the LLTVs subsequently crashed, one in which Neil Armstrong barely escaped. As part of the accident investigation, Langley was requested in 1969 to test a LLTV vehicle in the Full-Scale Tunnel, which once again provided a critical capability from a 38-year-old facility originally designed to test biplanes.

Following his LLTV accident, Neil Armstrong and Buzz Aldrin visited Langley for many hours of training with the LLRV before liftoff of Apollo 11 and its historic mission on July 11, 1969.

In addition to the LLRV activities which trained astronauts for moon landings, the LLRF was modified to provide a capability of experiencing reduced-gravity effects during walks on the moon. By suspending an astronaut (almost horizontally) so that one-sixth of his weight was applied to an inclined wall (almost vertical), researchers were able to simulate the correct gravitational field and allow the astronauts to train for tasks.

Not all of the Langley-developed simulators and concepts for Apollo were successful. One simulator known as the Lunar Orbit and Landing Approach (LOLA) simulator was a complex, expensive simulator intended to study the ability of the pilot to control the LEM from its separation from the Command and Service Modules during lunar orbit until it reached the desired landing area. This highly controversial simulator consisted of a large three-dimensional map which included lunar craters and other features machined into foam and painstakingly painted in accurate renditions of the surface. Built by the West Model Shop the machined foam panels were mounted to a large wall in the old Langley Aircraft Loads Hangar. A computer-controlled camera moved over the terrain model in the vicinity of the orbit. Images provided by the camera were projected on the interior wall of a 10-Foot diameter sphere housing the pilot’s cockpit.60

Above: History is made as the oldest NASA wind tunnel—the Langley Full-Scale Tunnel - is used for analysis of a crash of a Lunar Landing Training Vehicle in January 1969.

Left: Neil Armstrong After a practice session at the LLRF in February 1969.

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In addition to being very expensive and time-consuming, the LOLA simulator was regarded as a technical failure. Although the simulator worked as planned, the pilot’s display had to be cut off during the descent to land in order to protect the camera. In addition, simulation of the separation from the Command Module was a time-intensive activity involving very few pilot inputs for hours on end. The simulator was converted for studies of aircraft landing approaches and was later demolished when electronic displays were developed and physical terrain maps were no longer needed.

Arguably, the most important single contribution by Langley to the Apollo program was the concept of Lunar-Orbit Rendezvous. Without the LOR approach the United States could not have met Kennedy’s goal of placing an American on the moon within a decade. Langley’s conception of the remarkable rendezvous and docking simulator and the demonstrations of the relative ease of the task were key developments for Apollo.

The preparation of astronauts for landing on the moon and the experience of locomotion in the reduced gravity field of the moon are also acknowledged as critical contributions of Langley’s Lunar Landing Research Facility and the brilliant researchers that conceived and developed the hardware and operations required for the training.

Research Staff and Culture: The NASA Years

The creation of NASA brought major changes to the research staff and culture at Langley. From a technical perspective, the historical emphasis on aeronautics would be forever impacted by the urgency of the space program. The change of focus from aeronautics to space found many of the Langley researchers ill-prepared in the disciplines required to conduct the new space programs, and extensive efforts were made to educate the staff in pertinent topics relevant to space technology. Many of the young engineers were energized by the opportunities provided by the new research projects, especially since some senior organizational managers expressed their opinion that the field of aeronautics had matured to the point of diminishing returns.

Langley was named as the agency lead at the start up of NASA’s program, which involved the initiation and management of a massive effort unlike any project conducted in its aeronautics background. The Center immediately became a focal point of public and media

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interests, frequently appearing in national publications. Even the perception of Langley’s staff by local residents changed from “NACA Nuts” to “Brilliant” NASA scientists. A new cultural requirement rapidly evolved at all levels within the research organization—extensive public relations and interactions with the media.

After the creation of Project Mercury and the Space Task Group, massive transfers occurred from the traditional aeronautics facilities and organizations to the STG. Another major factor in the manpower shuffle was the fact that in 1958 NASA Headquarters decided that no further testing of high-speed airplanes would be conducted at Langley. Instead, all future high-speed flight research would be conducted at the NASA High-Speed Flight Station (now the NASA Dryden Flight Research Center). Rather than transferring to California, many of the very capable aircraft flight research staff became the nucleus of the STG and later became managers of the Apollo Program.

As the various elements of the Apollo program were pursued, it became obvious that the ability to conduct research on topics outside the major thrust of the program would not be permitted. For example, a growing effort among several Langley organizations to develop the technology required for a rotating manned space station was discovered by senior management and quickly stopped because it was not in line with the “mainstream” NASA mission. It was clear that the freedom to pursue new ideas that existed under the NACA would not be tolerated in NASA, and the projects had to be approved within the space program as directed by NASA Headquarters.

Another major cultural change at Langley was the fact that the center was no longer the lead center for the space program. The creation of Space Centers by NASA was motivated by the need to manage extremely large projects that would have inundated the traditional aeronautics Centers and resulted in the elimination of research by the so-called Field Centers.

Association with the Apollo Program also brought a new challenge to Langley personnel in the form of managing relatively large projects. Project Mercury had been managed by the STG, which was not formally a Langley organization, and the only previous management of large projects had been during the NACA days and the X-1 supersonic flight project. Within the Apollo activities Langley had to adopt the technical and administrative procedures of project management. Such arrangements resulted in technical people becoming managers and vice versa in many instances. However, the professional activity and results of highly successful projects

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such as the Scout Project, which developed an extremely successful and reliable launch vehicle for orbital missions, were evidence of Langley’s success. Project FIRE and the Lunar Orbiter Project also demonstrated the ability of the staff to become project oriented.

Yet another major change brought about by the magnitude of the space program was management’s philosophy of implementing contracts for numerous activities previously conducted by civil servants. Early on, such contracts covered maintenance and operations of critical systems such as computers, but the contracting mechanism quickly spread into supplying technical expertise on-site at Langley. The influx of contractors affected all aspects of business conducted by the research organizations and impacted funding resources as well as manpower levels.

Finally, after the formation of NASA, the Langley Research Center embraced an open-door policy toward the public and sponsored many highly attended open-house events. The NACA era had been notable for its lack of public access to the Langley laboratory and a general aura of secrecy. Access had been restricted to the technical community, VIPs, and on occasion, the media and politicians. In 1959 the Center hosted its first-ever open-house visit by the general public. Tens of thousands attended the event, and the public patiently waited in lines for hours for the gates to open for their first glimpse into the research activities conducted for the new space program. Thereafter, public drive-yourself tours were encouraged by management with great public participation. In 1971, the Center opened a new on-site Visitor Center featuring interesting and interactive displays of the history of Langley and technical programs underway at the time. The presence of the Visitor Center resulted in a dramatic increase in the public and media interest in NASA and an unprecedented level of on-site public presence that would continue until the 1990s when the functions of the visitor’s facility were transferred to a new Virginia Air and Space Center in downtown Hampton.

During the years of Mercury, Gemini, and Apollo, changes to the appearances of the Langley East Area and West Area were surprisingly moderate. Some construction efforts, such as a large new computer-complex building became landmarks of the West Area, although they were not specifically constructed for those programs. The most noticeable addition to the West Area was the huge Langley Lunar Landing Training Facility which dominated the landscape from miles away.

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Mission Accomplished

“Houston, Tranquility Base here. The Eagle has landed.”

With those words on July 20, 1969 Neil Armstrong announced to the world that the LEM had landed on the moon with about 25 seconds of fuel left. One of the most significant undertakings in the history of mankind had been accomplished within a time frame set by an ambitious President who never lived to see one of the proudest moments in American history. At Langley, many paused to reflect on the activities and contributions that had started decades earlier within its boundaries. In “Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo,” James Hansen wrote:

“By the time of Apollo 11’s historic first lunar landing on 20 July 1969, Langley’s multifarious R&D efforts for Apollo had been largely forgotten; except for the Hampton area press, the media gave the Center little attention. But without Langley, an American lunar landing that summer day may not have been possible.”

The magnitude of support for Apollo at Langley can be gauged by the number of projects undertaken by the Center from 1960 to 1968. During this period no less than 366 discrete Apollo-related projects were conducted by Langley organizations.

Today, historians look back on the early accomplishments of the fledging Langley Memorial Aeronautical Laboratory and how the pioneers in various disciplines contributed to the accelerated technology that was inherited and re-accelerated by the brilliant and dedicated researchers of the NASA Langley Research Center into the foundations of the manned space program. In view of the leadership and contributions that came from Langley, it is appropriate that formal recognition of the staff and facilities be forever embedded with mankind’s greatest achievement.

After the Apollo 11 mission, a sense of relief descended over the nation with a public perception that the threat of domination in outer space by the Soviet Union had been extinguished. Five additional Apollo missions were subsequently completed, but Americans quickly cooled in their support of the space program which had cost as much as $5 billion per year. To win the race to the moon, the nation had made the largest commitment of resources ($24 billion) ever made by any nation in peacetime. Coupled with the national trauma of Vietnam and race riots, President Nixon quickly deflated any enthusiasm for follow-on space programs. In 1972 NASA conducted the Apollo 16 and Apollo 17 flights and then ended the Apollo program.

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Chapter 4

Retrospective and Perspective

Recognizing Langley’s Significance

In 1985 the National Park Service (NPS) conducted a Man in Space theme study to identify nation-wide resources that made significant contributions to the Apollo Program. The study included consideration of wind tunnels, rocket engine facilities, launch complexes, training facilities, spacecraft and hardware test facilities, mission control and tracking centers, and other support facilities throughout the United States. After assessing NASA’s facilities, the NPS identified five unique facilities at the NASA Langley Research Center in the National Register as National Historic Landmarks (NHLs) in view of their critical contributions. The five Langley NHLs consist of three wind tunnels and two astronaut training facilities. The wind tunnels include the historic Langley Variable-Density Tunnel, the Langley 8-Foot High-Speed Tunnel, and the Langley Full-Scale Tunnel. These East Area facilities provided the fundamental aerodynamic understandings that led to the data base from which the early space program was initiated. The two training facilities named National Historic Landmarks were the Langley Rendezvous Docking Simulator and the Langley Lunar Landing Training Facility, both of which are located in the West Area. The facilities were critical in preparing astronauts to safely conduct the potentially catastrophic tasks of multi-vehicle docking, hundreds of thousands of miles from Earth, and landing on the moon.

In subsequent years NASA conducted more detailed follow-on cultural resource studies of 271 Langley facilities which resulted in an analysis of eligibility of the individual facilities for the National Register and a definition of the boundaries of Langley’s historic district. As a result of the scientific accomplishments to aeronautics and aerospace which occurred at NASA Langley, the entire center is eligible for listing in the National Register of Historic Places as the NASA LaRC Historic District, with a period of significance spanning 1917 to 1972

The NASA LaRC Historic District includes extant buildings and structures in both the East and West Areas that illustrate the major contributions and advances made by NASA researchers in the fields of aeronautics and space flight. The district is potentially eligible for listing in the National Register under Criterion A: Event and Criterion C: Design/Construction in the areas of science, engineering,

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military, communication, and transportation. The proposed district’s defined period of significance begins in 1917 coinciding with the establishment of the LMAL and the date of the earliest surviving facility, and ends with the conclusion of the Apollo program in 1972, thus Criteria Consideration G: Significance within the last fifty years applies.

Aerial view of the NASA Langley Research Center West Area.69

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ResourcesNASA Publications

James R. Hansen, Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917-1958, NASA SP-4305 (Washington, DC: GPO, 1986).

James R. Hansen, Spaceflight Revolution: NASA Langley research Center From Sputnik to Apollo, NASA SP-4308 (Washington, DC: GPO, 1995).

Donald D. Baals and William R. Corliss, Wind Tunnels of NASA, NASA SP-440 (Washington, DC: GPO, 1981).

James Schultz, Crafting Flight, NASA SP-2003-4316 (Washington, DC: GPO, 2003).

Books

George W. Gray, Frontiers of Flight: The Story of NACA Research (New York: Alfred A. Knopf, 1948).

Web Sites

NASA’s Cultural Resources (CRGIS) Web site has extensive documentation of major facilities and historical material including photographs and films: http://crgis.ndc.nasa.gov/historic/langley_research_center.

Book layout and cover, designed and illustrated by James Horatio Cato, Senior Graphic Designer, NASA Langley Research Center

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NP-2011-11-429-LaRC

National Aeronautics and Space AdministrationNASA Langley Research Center 100 NASA RoadHampton, VA 23681-2199

www.nasa.gov